Rounder is better on Wilier’s new Filante SLR flagship aero road racer

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Following hot on the heels of the recently announced Cento 10 SL and 0 SL mid-range bikes, Wilier today launched its third new road bike this calendar year. With the all-new Filante SLR road racer, Wilier has supposedly merged the aerodynamics of the Cento 10 Pro with the lower weight and ride characteristics of their 0 SLR to create a new flagship model that, of course, promises what we expect from almost every new bike launch now: lighter, faster, stiffer. 

Go ride outside

Although wind tunnel testing still played a major role on the new frame design, Wilier is keen to stress the importance that was placed on outdoor testing during the design process of the Filante SLR so as to better reflect real-world riding conditions – swirling winds, other riders, frequent changes in direction. Wilier didn’t provide precise details on the outdoor testing procedures, but said that as a result of this combined testing approach, the designers have made significant changes to the shapes previously used on other Wilier aero road bikes.

Wilier says the sharper-edged Kammtail tubing on the Cento 10 and other aero bikes is still very aerodynamic, but mostly at lower yaw angles – in other words, when the oncoming air is coming more directly head-on instead of in a crosswind direction. On the Filante SLR, those trailing edges are much more rounded with a less pronounced corner than before; the rest of the cross-section profile is still very similar. According to Wilier, the more rounded trailing edges retain more of those good aerodynamic properties at the higher yaw angles more commonly experienced out on the road, and when the rider chops and changes direction and experiences wind from different angles, the new frame is better able to maintain its good aerodynamic characteristics overall.

Grey can be associated with boring, but not on the Filante SLR.

The newly rounded tube shapes may not be immediately obvious when you see the Filante SLR for the first time. But it’s hard not to notice the new seatstays and fork blades.

Just over a year ago, Hope and Lotus launched the new British Cycling track bike in preparation for the Tokyo Olympics. That bikes features seatstays and fork blades that are positioned radically far apart, with the theory being that by increasing the space between the wheels and the fork legs and the seatstays, there is less turbulent air produced, and hence, less drag created. Arranging the fork blades, the rider’s legs, and the seatstay all directly behind each other is also said to cut down on aerodynamic drag.

A view of the new rounded trailing edge Kammtail down tube.

We all wondered at the time how long it would be until similar designs began to appear on road bikes, and now it seems Wilier has gone some way to delivering just that. Although far from as extreme as the track bike, Wilier has still increased the separation of both the fork blades and seatstays by 7 mm compared to the Cento 10 Pro while also keeping the extremely low dropped seatstays on the rear triangle. Wilier says the new wider design of the fork perfectly matches and hides the equally wide rear triangle further improving the aerodynamic properties of this new frame. Ironically (given Wilier’s emphasis on dual-mode aerodynamic testing), the benefit of this matching layout seems obvious when the bike is viewed head-on and perhaps plays out in the wind tunnel, but it’s questionable whether this theoretical improvement could be realized in real-world conditions out on the open road. 

The Filante SLR is not only claimed to be more aero than its predecessor; it should also be lighter. Compared to the sharper-edge design on previous models, the new rounder tube shapes require less material, which should result in a decrease in overall frame weight. In raw numbers, the Filante SLR weighs in at 870 g, which is just 90 g more than the 0 SLR, and an impressive weight for a dedicated aero frame. 

The fork blades and seatstays are intentionally very similar in shape, height, and width to potentially improve aerodynamics.

The Filante SLR shares more than just a focus on lower weight with the 0 SLR; Wilier has used the same unidirectional carbon and “liquid crystal polymers”. Wilier says the Filante SLR is 11% lighter than the Cento10 Pro while maintaining the same overall stiffness, resulting in a much-increased stiffness-to-weight ratio.

Five sizes fit all

Wilier has stuck with an integrated, one-piece carbon cockpit and also kept the perfectly horizontal stem with fully internal cable routing to further increase aerodynamics. Although Wilier has introduced a new range of sizes, the total range of choices is still very limited. In fact, Wilier is only offering five stem lengths, and bizarrely, these are 88, 101, 114, 127, and 140 mm. There’s no need to panic, though, as Wilier has supposedly chosen these lengths in combination with its new “Accufit” grid for sizing, and assures us that this new sizing actually offers more options for every rider. According to Wilier, and in combination with the new frame and spacer kits, the new cockpit offers 240 total possible combinations of measurements, all within 3 mm of the next and with no overlap whatsoever.

The new sizing options certainly seem to give the rider much more opportunity to dial in their fit, but how practical this is in the real world when ordering off a geometry sheet remains to be seen. Wilier has confirmed to us that an online tool will be launched soon that will allow riders to calculate which size of the new cockpit they need by simply inputting their current stack, reach, and stem lengths.

Fork steerer tubes are not usually a major topic of discussion when riders gather around a new bike. In fact, we could go as far as to say that steerer tubes are only ever the topic of discussion if they fail. However, Wilier has gone to great lengths in designing the steerer tube on the Filante SLR to increase stiffness and allow for fully internal cabling without increasing the frame’s frontal area. As part of this, Wilier has developed a proprietary headset with “superfine bearings” that we imagine will only be available from Wilier. This could mean that future availability and ease of replacement, especially when considering the hydraulic hoses which pass through the headset, might provide quite a headache (or service charge) when it does come time to replace the bearing. 

Wilier has always been synonymous with fabulous frame finishes, and that trend will continue on with the new Filante SLR. The Filante SLR will be available in velvet red, glossy grey, and matte black, all of which look great in the supplied photos. Conspicuously missing, though, is the gorgeous “remato” metallic copper paint color used elsewhere in the Wilier range. This may be due to the extra weight associated with the classic finish or it could be due to the fragile nature the chrome finish has been known for when applied to a carbon frame on previous models. Either way, I’m sad not to see it here.

Wide fork blades, a narrow head tube, internal cables: all very modern.

Prices start at €7,200 for the Filante SLR with Shimano Ultegra Di2, and will top out at €12,400 for a Campagnolo Super Record EPS build with Campagnolo Bora WTO 33 carbon wheels. For those after just a frameset, that will knock you back €5,000. Prices for other regions are to be confirmed.

The Filante SLR is shipping to dealers immediately so we should see these in the wild in the near future. Stay tuned for a proper review in the weeks and months ahead.

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